565
FXUS66 KMFR 222151
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
251 PM PDT Wed May 22 2024

.DISCUSSION...An upper level low pressure system has moved past the
area, but northwest flow behind the system will guide conditions
this evening. A Wind Advisory will continue until 8 PM tonight for
most of Lake County tonight to address gusty winds associated
with this system. This flow will also bring cooler nighttime
temperatures, with lows in the mid 20s to low 30s east of the
Cascades and in the low 30s to low 40s west of the Cascades. A
Frost Advisory is in place for Thursday morning between 3 AM and 8
AM for the Illinois and Applegate valleys as well as areas around
Rogue River and between White City and Shady Cove.

The pattern looks to remain active but unimpactful into next week. A
weak ridge will bring seasonal warmth on Thursday and a weak trough
will follow, lingering over the area to start the weekend. will cool
temperatures again on Friday. The trough will bring slight
precipitation chances over the Cascades (25-50%) from Friday evening
to Saturday evening. And for Friday evening, upper level instability
supports slight (10-15%) chances for thunderstorms over Lake, Modoc,
and eastern Klamath and Siskiyou counties. A more resilient upper
ridge follows on Sunday, bringing above average temperatures across
the area into the middle of next week. Next Wednesday`s daytime
highs will reach the mid 60s along the Oregon coast and low to mid
80s in west side valleys. Areas east of the Cascades are expected to
reach the mid to high 70s. Considering Brookings specifically,
models show periods of easterly winds that may cause a Chetco Effect
and bring higher than forecast temperatures, but that much detail is
difficult to determine with any confidence this far out.

There is substantial uncertainty in the forecast past next
Wednesday. Both the ECMWF and GFS models show the ridge moving east
with an upper trough related to a low pressure system bringing more
cool weather and scattered precipitation. The timing on this pattern
change varies by about 12 hours, with the ECMWF having the trough
arrive late Tuesday morning while the GFS expects a Tuesday
evening/Wednesday morning arrival. This uncertainty is also
reflected in NBM statistical guidance. For Thursday, the
interquartile range for Medford`s high temperature (25th through
75th ensemble percentile) is 72 to 88 degrees, and then 75 to 93
degrees next Friday. This indicated a fairly large degree uof
uncertainty. Long-term precipitation meteograms for both models
show a similar lack of confidence in a single outcome. This
disagreement grows into the end of next week, with ECMWF
deterministic imagery showing a developing ridge while the GFS
brings a low pressure system over the Pacific Northwest. -TAD

&&

.AVIATION...22/18Z TAFs...Gusty northwest winds will impact Medford
and Klamath Falls through early this evening then fairly quiet and
non-impactful aviation conditions are on tap through Thursday.
Stavish

&&

.MARINE...Updated 230 PM Wednesday, May 22, 2024...Conditions
hazardous to small craft will continue through the evening then seas
and winds lower overnight. Conditions improve under high pressure
Thursday with some gusty north winds developing nearshore south of
Cape Blanco in the afternoon. Another low pressure Friday brings
some light rain, then fair weather and benign winds and seas are
expected through the weekend.

&&

with
forecast temperatures falling between 75 and 93 degrees.
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Frost Advisory from 3 AM to 8 AM PDT Thursday for ORZ024-026.

     Wind Advisory until 8 PM PDT this evening for ORZ031.

CA...None.

PACIFIC COASTAL WATERS...Small Craft Advisory until 11 PM PDT this
     evening for PZZ350-356-370-376.

&&

$$